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#include "graphwidget.h"

#include "edge.h"

#include "node.h"

#include <QtGui>

#include <math.h>

//! [0]

GraphWidget::GraphWidget(QWidget *parent)

    : QGraphicsView(parent), timerId(0)

{

    QGraphicsScene *scene = new QGraphicsScene(this);

    scene->setItemIndexMethod(QGraphicsScene::NoIndex);

    scene->setSceneRect(-200, -200, 400, 400);

    setScene(scene);

    setCacheMode(CacheBackground);

    setViewportUpdateMode(BoundingRectViewportUpdate);

    setRenderHint(QPainter::Antialiasing);

    setTransformationAnchor(AnchorUnderMouse);

    scale(qreal(0.8), qreal(0.8));

    setMinimumSize(400, 400);

    setWindowTitle(tr("Elastic Nodes"));

//! [0]

//! [1]

    Node *node1 = new Node(this);

    Node *node2 = new Node(this);

    Node *node3 = new Node(this);

    Node *node4 = new Node(this);

    centerNode = new Node(this);

    Node *node6 = new Node(this);

    Node *node7 = new Node(this);

    Node *node8 = new Node(this);

    Node *node9 = new Node(this);

    scene->addItem(node1);

    scene->addItem(node2);

    scene->addItem(node3);

    scene->addItem(node4);

    scene->addItem(centerNode);

    scene->addItem(node6);

    scene->addItem(node7);

    scene->addItem(node8);

    scene->addItem(node9);

    scene->addItem(new Edge(node1, node2));

    scene->addItem(new Edge(node2, node3));

    scene->addItem(new Edge(node2, centerNode));

    scene->addItem(new Edge(node3, node6));

    scene->addItem(new Edge(node4, node1));

    scene->addItem(new Edge(node4, centerNode));

    scene->addItem(new Edge(centerNode, node6));

    scene->addItem(new Edge(centerNode, node8));

    scene->addItem(new Edge(node6, node9));

    scene->addItem(new Edge(node7, node4));

    scene->addItem(new Edge(node8, node7));

    scene->addItem(new Edge(node9, node8));

    node1->setPos(-50, -50);

    node2->setPos(0, -50);

    node3->setPos(50, -50);

    node4->setPos(-50, 0);

    centerNode->setPos(0, 0);

    node6->setPos(50, 0);

    node7->setPos(-50, 50);

    node8->setPos(0, 50);

    node9->setPos(50, 50);

}

//! [1]

//! [2]

void GraphWidget::itemMoved()

{

    if (!timerId)

        timerId = startTimer(1000 / 25);

}

//! [2]

//! [3]

void GraphWidget::keyPressEvent(QKeyEvent *event)

{

    switch (event->key()) {

    case Qt::Key_Up:

        centerNode->moveBy(0, -20);

        break;

    case Qt::Key_Down:

        centerNode->moveBy(0, 20);

        break;

    case Qt::Key_Left:

        centerNode->moveBy(-20, 0);

        break;

    case Qt::Key_Right:

        centerNode->moveBy(20, 0);

        break;

    case Qt::Key_Plus:

        scaleView(qreal(1.2));

        break;

    case Qt::Key_Minus:

        scaleView(1 / qreal(1.2));

        break;

    case Qt::Key_Space:

    case Qt::Key_Enter:

        foreach (QGraphicsItem *item, scene()->items()) {

            if (qgraphicsitem_cast<Node *>(item))

                item->setPos(-150 + qrand() % 300, -150 + qrand() % 300);

        }

        break;

    default:

        QGraphicsView::keyPressEvent(event);

    }

}

//! [3]

//! [4]

void GraphWidget::timerEvent(QTimerEvent *event)

{

    Q_UNUSED(event);

    QList<Node *> nodes;

    foreach (QGraphicsItem *item, scene()->items()) {

        if (Node *node = qgraphicsitem_cast<Node *>(item))

            nodes << node;

    }

    foreach (Node *node, nodes)

        node->calculateForces();

    bool itemsMoved = false;

    foreach (Node *node, nodes) {

        if (node->advance())

            itemsMoved = true;

    }

    if (!itemsMoved) {

        killTimer(timerId);

        timerId = 0;

    }

}

//! [4]

//! [5]

void GraphWidget::wheelEvent(QWheelEvent *event)

{

    scaleView(pow((double)2, -event->delta() / 240.0));

}

//! [5]

//! [6]

void GraphWidget::drawBackground(QPainter *painter, const QRectF &rect)

{

    Q_UNUSED(rect);

    // Shadow

    QRectF sceneRect = this->sceneRect();

    QRectF rightShadow(sceneRect.right(), sceneRect.top() + 5, 5, sceneRect.height());

    QRectF bottomShadow(sceneRect.left() + 5, sceneRect.bottom(), sceneRect.width(), 5);

    if (rightShadow.intersects(rect) || rightShadow.contains(rect))

	painter->fillRect(rightShadow, Qt::darkGray);

    if (bottomShadow.intersects(rect) || bottomShadow.contains(rect))

	painter->fillRect(bottomShadow, Qt::darkGray);

    // Fill

    QLinearGradient gradient(sceneRect.topLeft(), sceneRect.bottomRight());

    gradient.setColorAt(0, Qt::white);

    gradient.setColorAt(1, Qt::lightGray);

    painter->fillRect(rect.intersect(sceneRect), gradient);

    painter->setBrush(Qt::NoBrush);

    painter->drawRect(sceneRect);

    // Text

    QRectF textRect(sceneRect.left() + 4, sceneRect.top() + 4,

                    sceneRect.width() - 4, sceneRect.height() - 4);

    QString message(tr("Click and drag the nodes around, and zoom with the mouse "

                       "wheel or the '+' and '-' keys"));

    QFont font = painter->font();

    font.setBold(true);

    font.setPointSize(14);

    painter->setFont(font);

    painter->setPen(Qt::lightGray);

    painter->drawText(textRect.translated(2, 2), message);

    painter->setPen(Qt::black);

    painter->drawText(textRect, message);

}

//! [6]

//! [7]

void GraphWidget::scaleView(qreal scaleFactor)

{

    qreal factor = transform().scale(scaleFactor, scaleFactor).mapRect(QRectF(0, 0, 1, 1)).width();

    if (factor < 0.07 || factor > 100)

        return;

    scale(scaleFactor, scaleFactor);

}

//! [7]